Surface treating appliances such as vacuum cleaners are well known. The majority of vacuum cleaners are either of the “upright” type or of the “cylinder” type (also referred to canister or barrel machines in some countries). An upright vacuum cleaner typically comprises a main body containing dirt and dust separating apparatus, a pair of wheels mounted on the main body for maneuvering the vacuum cleaner over a floor surface to be cleaned, and a cleaner head mounted on the main body. The cleaner head has a downwardly directed suction opening which faces the floor surface. The vacuum cleaner further comprises a motor-driven fan unit for drawing dirt-bearing air through the suction opening. The dirt-bearing air is conveyed to the separating apparatus so that dirt and dust can be separated from the air before the air is expelled to the atmosphere. The separating apparatus can take the form of a filter, a filter bag or, as is known, a cyclonic arrangement.
In use, a user reclines the main body of the vacuum cleaner towards the floor surface, and then sequentially pushes and pulls a handle which is attached to the main body of the cleaner to maneuver the vacuum cleaner over the floor surface. The dirt-bearing air flow drawn through the suction opening by the fan unit is conducted to the separating apparatus by a first air flow duct. When dirt and dust has been separated from the air flow, the air flow is conducted to a clean air outlet by a second air flow duct. One or more filters may be provided between the separating apparatus and the clean air outlet.
An example of an upright vacuum cleaner with improved maneuverability is shown in WO2009/030885. This upright vacuum cleaner comprises a barrel-shaped rolling assembly located at the lower end of the main body for engaging the floor surface to be cleaned, and which rolls relative to the main body for allowing the main body to be rolled over the floor surface using the handle. The rolling assembly is rotatably connected between a pair of ducts which each extend to one side of the main body. The main body of the vacuum cleaner houses separating apparatus for separating dirt from a dirt-bearing air flow drawn into the cleaner head. To increase the stability of the vacuum cleaner, and to make efficient use of the space within the rolling assembly, the motor-driven fan unit for drawing dirt-bearing air into the suction opening is located within the rolling assembly.
A yoke extending about the external periphery of the rolling assembly connects the cleaner head to the main body. The yoke is pivotably connected between the ducts to allow the main body to be reclined relative to the yoke between an upright position and a reclined position for maneuvering the vacuum cleaner over a floor surface. The pivot axis of the yoke is substantially co-linear with the rotational axis of the rolling assembly. The cleaner head is connected to the forward, central part of the yoke by a joint which permits the yoke to be rotated relative to the cleaner head. These connections allow the main body to be rotated about its longitudinal axis, in the manner of a corkscrew, while the cleaner head remains in contact with the floor surface. As a result the cleaner head may be pointed in a new direction as the main body is rotated about its longitudinal axis. As the main body is pushed over the floor surface using the handle, the vacuum cleaner moves forward along the direction in which the cleaner head is pointed, thereby allowing the vacuum cleaner to be smoothly and easily maneuvered over the floor surface.
The vacuum cleaner comprises a stand for supporting the main body in its upright position, and which is moveable relative to the main body to a retracted position to allow the vacuum cleaner to be maneuvered over the floor surface when in its reclined position. The stand is moveable from the supporting position to the retracted position automatically in response to a force being applied to the main body to recline the main body from its upright position. An over center spring mechanism is provided for urging the stand towards one of its supporting and retracted positions depending on the position of the stand relative to the main body. An arrangement of levers and cam mechanisms may be provided to move the stand against the biasing force of the over center spring mechanism from its supporting and retracted positions. Alternatively, the yoke may be arranged to engage the stand as the main body is moved relative to the yoke from a reclined position to an upright position to urge the stand towards its supporting position against the biasing force of the over center spring mechanism.